Lower motion thresholds for rotational and radial flow have been measured for stimuli consisting of four closely packed circular apertures, each containing patches of drifting grating or plaid. Detection and direction thresholds were measured for gratings and plaids as a function of the relative orientation of the pattern components. There was a similarity between both types of threshold, supporting the existence of specialised rotation and radial-flow detectors. Further, thresholds increased with the relative component orientation for both gratings and plaids. This suggests that component information from a first stage, tuned spatiotemporally and to orientation, is being used directly to compute the optic flow in a two-stage process. A model based on this architecture is described by means of simple template receptive-field arrays with separable temporal and spatial tuning at the first stage.
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References
1.
AdelsonEBergenJ, 1985“Spatiotemporal energy models for the perception of motion”Journal of the Optical Society of America A2284–299
2.
AdelsonEMovshonJ, 1982“Phenomenal coherence of moving visual patterns”Nature (London)300523–525
3.
AndersonSBurrD, 1991“Spatial summation properties of directionally selective mechanisms in human vision”Journal of the Optical Society of America A81330–1339
4.
BraddickOHollidayI, 1991“Serial search for targets defined by divergence or deformation of optic flow”Perception20345–354
5.
DerringtonASueroM, 1991“Motion of complex patterns is computed from the perceived motions of their components”Vision Research31139–149
6.
DuffyCWurtzR, 1991a“Sensitivity of MST neurons to optic-flow stimuli. I. A continuum of response selectivity to large-field stimuli”Journal of Neurophysiology651329–1345
7.
DuffyCWurtzR, 1991b“Sensitivity of MST neurons to optic-flow stimuli. II. Mechanisms of response selectivity revealed by small-field stimuli”Journal of Neurophysiology651346–1359
8.
FerreraVWilsonH, 1990“Perceived direction of moving two-dimensional patterns”Vision Research30273–287
9.
FosterKGaskaJNaglerMPollenD, 1985“Spatial and temporal frequency selectivity of neurones in visual cortical areas V1 and V2 of the macaque monkey”Journal of Physiology (London)365331–363
10.
FreemanTHarrisM, 1992“Human sensitivity to expanding and rotating motion: Effects of complementary masking and directional structure”Vision Research3281–87
11.
GattassRGrossC, 1981“Visual topography of striate projection zone (MT) in posterior temporal sulcus of the macaque”Journal of Neurophysiology381500–1523
12.
GurneyKWrightM, 1992“A self-organising neural network model of image velocity encoding”Biological Cybernetics68173–181
13.
GurneyKWrightM, 1996“A biologically plausible model of early visual motion processing I: Theory and implementation”Biological Cybernetics (in press)
14.
JuleszBHesseR, 1970“Inability to perceive the direction of rotation movement of line segments”Nature (London)225243–244
KoenderinkJVan DoornA J, 1975“Invariant properties of the motion parallax field due to the movement of rigid bodies relative to an observer”Optica Acta22773–791
17.
LehkyS, 1985“Temporal properties of visual channels measured by masking”Journal of the Optical Society of America A21260–1272
18.
Longuet-HigginsHPrazdnyK, 1980“The interpretation of a moving retinal image”Proceedings of the Royal Society of London, Series B208385–397
19.
MaunsellJVan EssenD, 1983“The connections of the middle temporal visual area (MT) and their relationship to a cortical hierarchy in the macaque monkey”Journal of Neuroscience32563–2586
20.
MaunsellJNewsomeW, 1987“Visual processing in monkey extrastriate cortex”Annual Review of Neuroscience10363–401
21.
MovshonJAdelsonEGizziMNewsomeW, 1985“The analysis of moving visual patterns”, in Pattern Recognition Mechanisms Eds ChagasCGattasRGrossC, (Rome: Vatican Press) pp 117–151
22.
OrbanGLangeLVerriARaiguelSXiaoDMaesHTorreV, 1992“First-order analysis of optical flow in monkey brain”Proceedings of the National Academy of Science of the United States of America892595–2599
23.
PerroneJ, 1992“Model for the computation of self-motion in biological systems”Journal of the Optical Society of America A9177–194
24.
ReganDBeverleyK, 1978“Looming detectors in the human visual pathway”Vision Research18415–421
25.
ReganDBeverleyK, 1980“Visual responses to changing size and to sideways motion for different directions in depth: Linearization of visual responses”Journal of the Optical Society of America701289–1296
26.
ReganDBeverleyK, 1985“Visual responses to vorticity and the neural analysis of optic flow”Journal of the Optical Society of America A2280–283
27.
SekulerA, 1992“Simple-pooling of unidirectional motion predicts speed discrimination for looming stimuli”Vision Research322277–2288
28.
SmithA, 1991“Perceived speed and direction of complex gratings and plaids”Journal of the Optical Society of America A81161–1171
29.
StoneLWatsonAMulliganJ, 1990“Effect of contrast on the perceived direction of a moving plaid”Vision Research301049–1067
30.
TanakaKFukadaYSaitoH, 1989“Underlying mechanisms of the response specificity of expansion/contraction, and rotation cells clustered in the dorsal part of the medial superior temporal area of the macaque monkey”Journal of Neurophysiology62642–656
31.
TanakaKSaitoH, 1989“Analysis of the motion of the visual field by direction, expansion/contraction, and rotation cells clustered in the dorsal part of the medial superior temporal area of the macaque monkey”Journal of Neurophysiology62626–641
32.
ThompsonP, 1984“The coding of velocity of movement in the human visual system”Vision Research2441–45
33.
VallortigaraGBressanP, 1991“Occlusion and the perception of coherent motion”Vision Research311967–1978
34.
WatsonARobsonJ, 1981“Discrimination at threshold: Labelled detectors in human vision”Vision Research211115–1122
35.
WelchL, 1989“The perception of moving plaids reveals two motion-processing stages”Nature (London)373734–736
36.
WerkhovenPKoenderinkJ, 1991a“Reversed rotary motion perception”Journal of the Optical Society of America A81510–1516
37.
WerkhovenPKoenderinkJ, 1991b“Visual processing of rotary motion”Perception & Psychophysics4973–82
38.
WetherillGLevittH, 1965“Sequential estimation of points on a psychometric function”The British Journal of Mathematical and Statistical Psychology181–10
39.
WilsonHGieseS, 1977“Threshold visibility of frequency gradient patterns”Vision Research171177–1190
40.
WrightMGurneyK, 1992“Lower threshold of motion for one- and two-dimensional patterns in central and peripheral vision”Vision Research32121–134
41.
WrightMGurneyK, 1995“The discrimination of dynamic orientation changes in gratings”Perception24665–679
